While there has been progress in developing an AIDS vaccine, there is as yet no truly effective vaccine to prevent HIV-1 transmission. This project will provide tissue analysis technologies such as in situ hybridization and tetramer staining, immunochemistry, and combinations thereof to investigators who will use these methods to assess impact and mechanisms of vaccine strategies on the natural history of vaginal transmission and acute systemic infection in the SlV/SHIV-rhesus macaque animal model.